1. Field of the Invention
The present invention relates to a liquid ejection head, a liquid ejection unit, and a liquid ejection device.
2. Description of the Related Art
A liquid ejection head for use in an image recording apparatus or image forming apparatus, such as a printer, a facsimile machine, or a copier, is known, which includes a nozzle to eject ink droplets, a pressure chamber in communication with the nozzle, and an electromechanical transducer element, such as a piezoelectric element, to pressurize the ink in the pressure chamber. Further, two types of liquid ejection heads are put in practical use, one type using an actuator of longitudinal vibration mode, and the other type using an actuator of flexural vibration mode.
For example, there is known a liquid ejection head of the type using the actuator of flexural vibration mode, which includes a layer of a piezoelectric material uniformly formed on an overall surface of a diaphragm by using a film deposition technique. In this liquid ejection head, an electromechanical transducer element is fabricated by forming the piezoelectric material layer into a shape corresponding to a shape of a pressure chamber by using a lithographic process, so that one electromechanical transducer element is provided independently for one pressure chamber. In this liquid ejection head, the diaphragm is bent in a convex form which projects toward the pressure chamber side, and the diaphragm has an amount of deflection. For example, see Japanese Patent No. 3555682 and Japanese Laid-Open Patent Publication No. 2014-151511.
In the above-described liquid ejection head according to the related art, the amount of deflection of the diaphragm on which a single electromechanical transducer element is mounted is taken into consideration. However, a distribution of the amounts of deflection of the diaphragm on which plural electromechanical transducer elements are mounted is not taken into consideration. Hence, in a case of a liquid ejection head in which plural electromechanical transducer elements are arrayed, it is difficult to obtain stable ink ejection characteristics.